Physiological and genome-wide RNA-sequencing analyses identify candidate genes in a nitrogen-use efficient potato cv. Kufri Gaurav.

Nitrogen (N) is an important nutrient for plant growth. However, its excess application leads to environmental damage. Hence, improving nitrogen use efficiency (NUE) of plant is one of the plausible options to solve the problems. Aim of this study was to identify candidate genes involved in enhancing NUE in potato cv. Kufri Gaurav (N efficient). Plants were grown in aeroponic with two contrasting N regimes (low N: 0.75 mM, and high N: 7.5 mM). Higher NUE in Kufri Gaurav was observed in low N based on the parameters like NUE, NUpE (N uptake efficiency), NUtE (N utilization efficiency) and AgNUE (agronomic NUE). Further, global gene expression profiles in root, leaf and stolon tissues were analyzed by RNA-sequencing using Ion Proton™ System. Quality data (≥Q20) of 2.04-2.73 Gb per sample were mapped with the potato genome. Statistically significant (P ≤ 0.05) differentially expressed genes (DEGs) were identified such as 176 (up-regulated) and 30 (down-regulated) in leaves, 39 (up-regulated) and 105 (down-regulated) in roots, and 81 (up-regulated) and 694 (down-regulated) in stolons. The gene ontology (GO) terms like metabolic process, cellular process and catalytic activity were predominant. Our RT-qPCR analysis confirmed the gene expression profiles of RNA-seq. Overall, we identified candidate genes associated with improving NUE such as superoxide dismutase, GDSL esterase lipase, probable phosphatase 2C, high affinity nitrate transporters, sugar transporter, proline rich proteins, transcription factors (VQ motif, SPX domain, bHLH) etc. Our findings suggest that these candidate genes probably play crucial roles in enhancing NUE in potato.

Genome sequencing of four strains of Phylotype I, II and IV of Ralstonia solanacearum that cause potato bacterial wilt in India

Abstract Ralstonia solanacearum is a heterogeneous species complex causing bacterial wilts in more than 450 plant species distributed in 54 families. The complexity of the genome and the wide diversity existing within the species has led to the concept of R. solanacearum species complex (RsSC). Here we report the genome sequence of the four strains (RS2, RS25, RS48 and RS75) belonging to three of the four phylotypes of R. solanacearum that cause potato bacterial wilt in India. The genome sequence data would be a valuable resource for the evolutionary, epidemiological studies and quarantine of this phytopathogen.

Genome sequencing of four strains of Phylotype I, II and IV of Ralstonia solanacearum that cause potato bacterial wilt in India.

Ralstonia solanacearum is a heterogeneous species complex causing bacterial wilts in more than 450 plant species distributed in 54 families. The complexity of the genome and the wide diversity existing within the species has led to the concept of R. solanacearum species complex (RsSC). Here we report the genome sequence of the four strains (RS2, RS25, RS48 and RS75) belonging to three of the four phylotypes of R. solanacearum that cause potato bacterial wilt in India. The genome sequence data would be a valuable resource for the evolutionary, epidemiological studies and quarantine of this phytopathogen.

Genome sequence and analysis of the tuber crop potato.

Potato (Solanum tuberosum L.) is the world's most important non-grain food crop and is central to global food security. It is clonally propagated, highly heterozygous, autotetraploid, and suffers acute inbreeding depression. Here we use a homozygous doubled-monoploid potato clone to sequence and assemble 86% of the 844-megabase genome. We predict 39,031 protein-coding genes and present evidence for at least two genome duplication events indicative of a palaeopolyploid origin. As the first genome sequence of an asterid, the potato genome reveals 2,642 genes specific to this large angiosperm clade. We also sequenced a heterozygous diploid clone and show that gene presence/absence variants and other potentially deleterious mutations occur frequently and are a likely cause of inbreeding depression. Gene family expansion, tissue-specific expression and recruitment of genes to new pathways contributed to the evolution of tuber development. The potato genome sequence provides a platform for genetic improvement of this vital crop.